CVE-2025-59517 Overview
CVE-2025-59517 is an improper access control vulnerability [CWE-284] in the Windows Storage Virtual Service Provider (VSP) Driver. An authenticated local attacker can exploit the flaw to elevate privileges on the target system. Microsoft published the advisory on December 9, 2025, and the issue affects a broad range of Windows client and server releases, including Windows 10, Windows 11, and Windows Server 2016 through Windows Server 2025.
Successful exploitation grants full confidentiality, integrity, and availability impact on the local host. The vulnerability requires low privileges and no user interaction, making it a practical post-compromise tool for attackers seeking SYSTEM-level access.
Critical Impact
A low-privileged local user can escalate to SYSTEM by abusing improper access checks in the Storage VSP Driver, enabling full control of the affected Windows host.
Affected Products
- Microsoft Windows 10 (1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (23H2, 24H2, 25H2)
- Microsoft Windows Server 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2025-12-09 - CVE-2025-59517 published to NVD
- 2025-12-09 - Microsoft releases security update for CVE-2025-59517
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-59517
Vulnerability Analysis
The Windows Storage VSP Driver mediates storage operations between guest partitions and the host in Hyper-V environments and supports virtualized storage stacks on modern Windows builds. The driver exposes device objects and I/O control interfaces reachable from user mode. An authenticated attacker with a standard user context can interact with these interfaces to perform actions the driver should restrict to higher-privileged callers.
Because the driver runs in kernel mode, successful abuse yields code or object manipulation at SYSTEM. The attack requires local access only, and Microsoft has not indicated exploitation in the wild. However, the EPSS probability of 2.329% (82nd percentile) reflects meaningful attacker interest relative to typical CVEs.
Root Cause
The flaw is categorized under [CWE-284] Improper Access Control. The Storage VSP Driver fails to correctly validate the security context of a caller before granting access to privileged operations or objects. An authorized but low-privileged process can therefore invoke functionality reserved for elevated principals.
Attack Vector
Exploitation is local. An attacker must already have code execution as a standard user, for example through a phishing payload, a compromised service account, or lateral movement. The attacker then issues crafted I/O requests to the Storage VSP Driver to trigger the privileged operation. No user interaction is required. Detailed exploitation primitives have not been published by Microsoft; see the Microsoft Security Update CVE-2025-59517 advisory for vendor guidance.
Detection Methods for CVE-2025-59517
Indicators of Compromise
- Unexpected loading of or handles opened to the Storage VSP Driver device object by non-system processes.
- New services, scheduled tasks, or local administrator accounts created shortly after a standard user process interacts with storage-related device interfaces.
- Process token elevation events where a low-integrity process gains SYSTEM privileges without a documented parent-child chain.
Detection Strategies
- Correlate Windows Security Event ID 4688 (process creation) with subsequent Event ID 4672 (special privileges assigned) originating from unexpected user processes.
- Hunt for anomalous DeviceIoControl calls against storage virtualization device objects issued from non-administrative sessions.
- Baseline kernel driver activity on Hyper-V hosts and flag deviations in Storage VSP Driver caller identities.
Monitoring Recommendations
- Ensure Sysmon or equivalent kernel telemetry is enabled with driver load, process creation, and token manipulation events forwarded to central logging.
- Track patch compliance for the December 2025 Microsoft security updates across all Windows client and server endpoints.
- Alert on privilege escalation sequences that immediately follow interaction with virtualization or storage driver interfaces.
How to Mitigate CVE-2025-59517
Immediate Actions Required
- Apply the December 2025 Microsoft security update for CVE-2025-59517 to all affected Windows 10, Windows 11, and Windows Server systems.
- Prioritize patching Hyper-V hosts and multi-tenant servers where local privilege escalation has the highest blast radius.
- Audit local accounts and remove unnecessary interactive logon rights to reduce the pool of potential attackers.
Patch Information
Microsoft has released security updates through the standard Windows Update channel. Refer to the Microsoft Security Update CVE-2025-59517 guide for the specific KB numbers that map to each supported Windows build.
Workarounds
- No official workaround has been published by Microsoft; patching is the required remediation.
- Restrict local logon and remote desktop access to trusted administrative accounts to reduce exposure until patches are deployed.
- Enforce application control policies such as Windows Defender Application Control (WDAC) or AppLocker to block unauthorized binaries that could stage a local exploit.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
